Measuring the ______ of the electrolyte provides an indication of a battery's state of charge
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Answer: D. specific gravity
Explanation
Specific gravity measures electrolyte density relative to pure reference water. Sulfuric acid is consumed during discharge, lowering the overall density of the liquid. Recharging releases acid back into solution, raising the specific gravity readings. Hydrometers are standard handheld tools used to measure electrolyte specific gravity. Electrolyte concentration correlates directly with the state of charge in lead-acid cells. Temperature compensation is applied to hydrometer readings for accurate state assessments.
Technicians check specific gravity regularly during routine maintenance of backup battery banks. A low specific gravity reading indicates a discharged or sulfated battery requiring a charge. Monitoring electrolyte density helps detect failing individual cells within a large battery string. Electrolyte color remains largely unchanged during normal charging and discharging cycles. Mass measurements of liquid volume are impractical for field state-of-charge checks. Viscosity changes are too subtle to serve as reliable indicators of battery charge state.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
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